currently have little over 6000 miles on this 08 Mazda3 S touring H.B.
Bought it new and on the first gas tank got 411 miles or 28 miles per gallon.
This car has a 14.5 gallon tank as it said in the manual.

I use super unleaded (different brands) on this car from day one. ever since that first gas tank, I get 280-286 miles per tank in times when not using AC, and now that is AC season I just got 220 my last gas tank.

I have switched to Regular and Med grade gas, but end up getting much worst results.

I have also used Ethanol free gasoline (super) and after the second tank, I started to see a big difference. at least 30-50 miles increase.

Google for Ethanol free gasoline stations in your area see if it helps.

I also have mixed feelings about factory Good year tires that came with this car and am debating to replaced them with a different brand, as tires are known to be a problem to gas mileage issues.

 

Using Med and Super Unleaded WILL give you worse gas mil. The octane rating relates to the point, heat and compression, that the gas will ignite at to give you the best efficiency.

So in other words, using a higher grade gas in a non-turbo stock engine, as yours, is not capable of using the fuel to its full potential in a engine that is not designed for it, so in turn will only burn a portion of the fuel and waste the rest.

But if you want to continue to throw your money out your tailpipe, litterally, be my guest.

Also, yes the tires are junk, but your not going to see a huge difference in MPG due to tires, inflation is important, but still not a world revolation on the oil crisis.

 

I ran 100% Regular gas until they could not get it anymore at the local station, was getting on the average 32-34 MPG, when running 10% Ethanol in the gas I was getting 2-4 MPG less.
We have many Gas stations around here that sell E85 regular, but without having a Vehicle that is made for Flex fuel I won't run it, since there are many things that could be screwed up. Also, not many will remember Gasohol (50/50 mix) from the late 70's early 80's but every car I ran it in got much worse mileage.
BTW, the best Mileage ever achieved in my car (2008.5 Mazda 3 Sport HB) was 37.34 on regular gas with the yellow light on saying I was low and putting over 12 gallons, but by your posted figures you burnt 14.67 gallons of gas, awful trusting of your brand new cars nonexistent gas reserves or you meant to put a 3 in instead of a 4. I was always getting 325 mile or better on a tank of Regular gas in mine.

 

I tried using Regular and Med grade Unleaded and end up getting much worst results. 30-35 miles less compared to using super.

I went back to Super and got back to that 280 per tank range.

There is something fishy with the gasoline we are using.
I think it's The Ethanol, but time will tell.

Peace.

 

I have to tell you, there is simply no way to accurately compare fuel economy on the open road (hence the fact that your results are considered scientifically irrelevant "anecdotal" observations), at least no way to do it with consistently verifiable results. The only reason (and I mean the ONLY reason) why your car might have gotten better mileage from the Premium fuel versus the Regular fuel is if (unlike here in New England) your Premium fuel has less (or no) ethanol compared to your regular gasoline. Even then the difference will only amount to something less than 5%.

 

I don't know what kind of driving you all are doing but I consistently get 400-415 miles per tank in my 2006.

If you are doing a lot of starting/stopping/idling then that makes a difference as compared to mostly highway driving.

I drive alot (have 140K miles on my car) and have only ever used standard octane gas.

I drive mostly highway but also have a decent mix of stopping/starting as highway driving here in the DC area is not quite 'fast'.

Even with using my AC a bit more I haven't noticed a drop at all in my mileage. I drive generally drive to keep up with traffic so I'm not just driving 55.

I don't know...it's worked for me for 4 years so far so I'm not going to complain.

 

can we run with ethanol in the Mazda 6? I have the 2.3 liter I4 engine? I would do anything to make my baby run even better.

 

Define "run with ethanol".

If you mean, "Can we run E85 in the Mazda6?" I'm betting the answer is "no" as no Mazda that I'm aware of that is sold in the Americas is designed for "Flex-Fuel". That said, the chances are that even if you did somehow have a Flex-Fuel engine, it would still run significantly worse on E85 versus 100% gasoline (or even E10 that most parts of the country are getting now-adays).

If you are asking if it is acceptable to run gasoline with up to 10% ethanol (i.e. E10), yes, all cars sold in the Americas have been specifically designed to run with E10 for a rather long time now.

 

Been watchin my milage for 2 months now and I get approximatly 400 miles per tank and I use 87 octane regular unleaded gas, that's with 10% ethenol. Haven't noticed much difference when using the A/C alot. Kinda funny reading about a bunch of people with tiny little 4cyl engines worring about gas milage. LOL So would you worry about milage if you had a big ford V8? Or would that be a mute point? I'm guessing so. At any rate I'm thinking this car get some great mileage and I like driving it so I'm not gonna worry about it, just enjoy it. I don't think this car is the answer to our oil problems but hey can a prius be that fun to drive?